Achieving stable interphases toward lithium metal batteries by a dilute and anion-rich electrolyte

It is necessary to find an ideal electrolyte suitable for high performance lithium metal batteries (LMBs). Herein, we construct a novel cluster-like and anion-rich dilute electrolyte system by using LiNO 3 and trace lithium trifluoromethanesulfonate (LiOTf) in an ester-based electrolyte. In the designed system, NO 3 – is used as a modulator to regulate the coordination number of solvents and anions, and LiOTf is applied as a solubilizing agent of LiNO 3 and trigger for the generation of large cluster. As a result, an anion-regulated solvation structure (ARSS) is obtained even in a dilute Li-ion concentration (<1.5 M), evidenced by various techniques, enabling the electrolyte a high ion-conductivity which vastly differs from a high concentration electrolyte system. Afterwards, the ARSS facilitates the formation of an inorganic-rich solid electrolyte interface (SEI) on both cathode and anode , ensuring the LMBs high stability and long cycling performance. An anion regulated solvation structure (ARSS) model is designed for lithium metal batteries (LMBs) to improve cycling stability. In the designed system, NO 3 – is used as a modulator to regulate the coordination number of solvents and anions, and LiCF 3 SO 3 (LiOTf) is applied as a solubilizing agent of LiNO 3 and trigger for the generation of large cluster. As a result, anion-dominated and cluster-based solvated structure is obtained even in a dilute Li-ion concentration (<1.5 M), which dominates the composition of the inorganic-rich SEI. The robust SEI effectively protects the cathode and anode, enhancing the cycling stability.